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A181716
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a(n) = a(n-1) + a(n-2) + (-1)^n, with a(0)=0 and a(1)=1.
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4
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0, 1, 2, 2, 5, 6, 12, 17, 30, 46, 77, 122, 200, 321, 522, 842, 1365, 2206, 3572, 5777, 9350, 15126, 24477, 39602, 64080, 103681, 167762, 271442, 439205, 710646, 1149852, 1860497, 3010350, 4870846, 7881197, 12752042, 20633240, 33385281, 54018522, 87403802
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OFFSET
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0,3
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COMMENTS
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Aside from the first term, duplicate of A098600.
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LINKS
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FORMULA
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a(n) = a(n-1) + a(n-2) + (-1)^n.
a(n) = 2*a(n-2) + a(n-3).
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MATHEMATICA
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a[0]= 0; a[1]= 1; a[n_]:= a[n]= a[n-1] +a[n-2] +(-1)^n; Array[a, 38, 0]
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PROG
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(Magma) I:=[0, 1, 2]; [n le 3 select I[n] else 2*Self(n-2)+Self(n-3): n in [1..40]]; // Vincenzo Librandi, Jan 09 2012
(Magma) [Lucas(n-1)+(-1)^n: n in [0..40]]; // G. C. Greubel, Mar 25 2024
(SageMath) [lucas_number2(n-1, 1, -1)+(-1)^n for n in range(41)] # G. C. Greubel, Mar 25 2024
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CROSSREFS
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KEYWORD
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easy,nonn
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AUTHOR
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STATUS
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approved
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